Method for forming Ge-Sb-Te film and storage medium

Abstract

Disclosed is a method for forming a Ge—Sb—Te film, in which a substrate is disposed within a process chamber, a gaseous Ge material, a gaseous Sb material, and a Te material are introduced into the process chamber, so that a Ge—Sb—Te film formed of Ge 2 Sb 2 Te 5 is formed on the substrate by CVD. The method for forming a Ge—Sb—Te film comprises: a step (step 2 ) wherein the gaseous Ge material and the gaseous Sb material or alternatively a small amount of the gaseous Te material not sufficient for formed of Ge 2 Sb 2 Te 5 in addition to the gaseous Ge material and the gaseous Sb material are introduced into the process chamber so that a precursor film, which does not contain Te or contains Te in an amount smaller than that in Ge 2 Sb 2 Te 5 , is formed on the substrate; and a step (step 3 ) wherein the gaseous Te material is introduced into the process chamber and the precursor film is caused to adsorb Te, so that the Te concentration in the film is adjusted.

What is claimed is: 
     
       1. A method of forming a Ge—Sb—Te film formed of Ge 2 Sb 2 Te 5  on a substrate by CVD by disposing the substrate in a process chamber and using a gaseous Ge material, a gaseous Sb material, and a gaseous Te material, the method comprising:
 introducing the gaseous Ge material and the gaseous Sb material, or a small amount of the gaseous Te material not sufficient to form Ge 2 Sb 2 Te 5  in addition to the gaseous Ge material and the gaseous Sb material into the process chamber so that a precursor film which does not contain Te or contains Te in an amount smaller than that in Ge 2 Sb 2 Te 5  is formed on the substrate; 
 after forming the precursor film, introducing the gaseous Ge material into the process chamber to cause Ge to be adsorbed to the precursor film; and 
 after Ge is adsorbed to the precursor film by introducing the gaseous Ge material into the process chamber, introducing the gaseous Te material into the process chamber to cause Te to be adsorbed to the precursor film so that the concentration of Te in the precursor film is adjusted, 
 wherein when forming the precursor film, the gaseous Ge material and the gaseous Sb material or the small amount of the gaseous Te material not sufficient to form Ge 2 Sb 2 Te 5  in addition to the gaseous Ge material and the gaseous Sb material are supplied in a lump, and 
 wherein the precursor film contains Ge in an amount smaller than that in Ge 2 Sb 2 Te 5 . 
 
     
     
       2. The method of  claim 1 , further comprising causing Ge to be adsorbed to the precursor film again, which is performed after Ge is adsorbed to the precursor film and then Te is adsorbed to the precursor film. 
     
     
       3. The method of  claim 1 , wherein the Ge material and the Sb material are a Ge compound that contains an amino group or an amidine group and an Sb compound that contains an amino group or an amidine group, respectively, and when forming the precursor film, a reaction gas that decomposes the amino group or the amidine group is supplied simultaneously with the Ge compound and the Sb compound. 
     
     
       4. The method of  claim 3 , wherein the Te material is a compound that contains an alkyl group.